科學(xué)60秒:冥王星衛(wèi)星身世之謎
來源：滬江聽寫酷
2011-07-11 10:00
Imagine a pinball machine on multi-ball mode—only the balls are the size of planets. The early solar system was such a rough-and-tumble place.
That ____1____ environment produced the occasional literally Earth-shattering collision. The moon, for instance, is believed to have formed from debris ____2____ by a Mars-size object careening into our young planet.
Now, new research indicates that Pluto may have suffered a similar fate. According to planetary scientist Robin Canup, all three of Pluto’s satellites could ____3____ to a single impact.
An impact has long been ____4____ for the birth of Charon, the largest Plutonian moon, but Canup ran impact simulations to show that Nix and Hydra, two much smaller satellites discovered in 2005, may be debris from the same collision. Her study appears in The Astronomical Journal.
A simulated low-speed crash between two____5____ sized planetoids yields a Pluto and a Charon, plus an icy debris disk that could coalesce into a Nix and a Hydra. That means that the small satellites should still be pretty icy—a prediction that may be tested as soon as 2015, when NASA’s New Horizons probe reaches the area. If the probe finds that Nix and Hydra are mostly ice, it'll show Canup’s simulation to be a smashing success.
【視聽版科學(xué)小組榮譽(yù)出品】
That ____1____ environment produced the occasional literally Earth-shattering collision. The moon, for instance, is believed to have formed from debris ____2____ by a Mars-size object careening into our young planet.
Now, new research indicates that Pluto may have suffered a similar fate. According to planetary scientist Robin Canup, all three of Pluto’s satellites could ____3____ to a single impact.
An impact has long been ____4____ for the birth of Charon, the largest Plutonian moon, but Canup ran impact simulations to show that Nix and Hydra, two much smaller satellites discovered in 2005, may be debris from the same collision. Her study appears in The Astronomical Journal.
A simulated low-speed crash between two____5____ sized planetoids yields a Pluto and a Charon, plus an icy debris disk that could coalesce into a Nix and a Hydra. That means that the small satellites should still be pretty icy—a prediction that may be tested as soon as 2015, when NASA’s New Horizons probe reaches the area. If the probe finds that Nix and Hydra are mostly ice, it'll show Canup’s simulation to be a smashing success.
【視聽版科學(xué)小組榮譽(yù)出品】
chaotic stirred up trace back suspected comparably
想象一下一個(gè)多球模式的彈球機(jī)——不過球的大小和行星差不多。早期的太陽系就是這么個(gè)混亂的地方。 在混亂的環(huán)境會(huì)不時(shí)發(fā)生驚天動(dòng)地的碰撞（雙關(guān)了，不明白的同學(xué)可以去討論帖^-^）。舉個(gè)例子，人們相信某顆火星大小的行星和一顆年輕行星碰撞后，產(chǎn)生的碎屑形成了月球。 現(xiàn)在一項(xiàng)新研究表示，冥王星的命運(yùn)何能如出一轍。行星科學(xué)家羅賓?克納普表示，冥王星的三顆衛(wèi)星都是由某次沖撞產(chǎn)生的。 長期以來，人們都在推測卡戎——最大的冥王星衛(wèi)星——產(chǎn)生于某次沖撞，但克納普用模擬沖撞證明尼克斯和許德拉——兩顆在2005年發(fā)現(xiàn)的小一號衛(wèi)星——可能也是由同一次沖撞產(chǎn)生的。她的研究刊登在《天文期刊》上。 兩顆相似大小的行星在模擬低速碰撞中產(chǎn)生了冥王星和卡戎，還有可以形成尼克斯和許德拉的并碎屑。這意味著兩顆小衛(wèi)星現(xiàn)在應(yīng)該還是冰天雪地的，而2015年久可以檢驗(yàn)這個(gè)預(yù)言的真假了，到時(shí)美國宇航局新視野號探測器就可以到達(dá)那個(gè)領(lǐng)域。如果探測器發(fā)現(xiàn)尼克斯和許德拉上多數(shù)都是冰，那么克納普的模擬實(shí)驗(yàn)真是個(gè)巨大的成功了。
